[Show abstract][Hide abstract] ABSTRACT: This paper describes a method to fabricate gadolinium hydroxide (Gd(OH)3) nanoparticles. An opaque solution was prepared by adding basic anion exchange resin (BAER) to a Gd(NO3)3 aqueous solution at room temperature and aging the solution for 12–24 h; the solution became basic because of the exchange of H2O with OH−. The particles in the opaque solution have a needle structure, and their crystal structure was hexagonal Gd(OH)3. Their longitudinal and lateral average particle sizes tend to increase in the ranges of 175.0–222.1 and 33.9–52.3 nm when the aging time increases from 12 to 24 h, respectively. The relaxivity value for T1-weighted imaging was 0.79 mM−1 s−1 for the solution that was prepared at the aging time of 18 h, which was ca. 20% of that for a commercial Gd complex contrast agent.
[Show abstract][Hide abstract] ABSTRACT: This study proposes a method for preparing high-concentration silica-coated Au (Au/SiO2) nanoparticles in colloidal solution from 1.5 × 10−3 M hydrogen tetrachloroaurate (III) trihydrate as the Au source and 1.0 × 10−2 M sodium citrate as the reducing reagent. The colloidal solution is applied to X-ray computed tomography (CT) imaging of mouse tissue. The Au nanoparticles in the colloidal solution had a diameter of 18.9 nm, and the Au concentration reached 1.5 × 10−3 M. The Au nanoparticles were silica-coated by modifying their surfaces with (3-aminopropyl)trimethoxysilane (APMS), then depositing silica nuclei generated by a sol–gel reaction of tetraethyl orthosilicate (TEOS) in water/ethanol initiated with sodium hydroxide (NaOH) on the surface modified with APMS. A colloidal solution of Au/SiO2 core–shell particles (silica shell thickness = 19.7 nm) was formed in a final as-prepared solution of 2.7 × 10−4 M Au, 2.0 × 10−5 M APMS, 24 M H2O, 1.9 × 10−3 M NaOH, and 4.1 × 10−3 M TEOS. The Au in the as-prepared colloidal solution was further concentrated to 0.27 M by salting-out and centrifugation. The CT value of the concentrated Au/SiO2 colloidal solution was 2.52 × 103 Hounsfield units, double that of a commercial X-ray contrast agent with the same I concentration as the Au concentration. When injected into mouse tissue, the Au/SiO2 colloidal solution demonstrated good imaging capability.
No preview · Article · Dec 2015 · Journal of Sol-Gel Science and Technology
[Show abstract][Hide abstract] ABSTRACT: Pure nanodrugs (PNDs) is a newly designed drug materials, which is a carrier-free drug nanoparticles fabricated by the reprecipitation method. In the present study, the cytotoxicity of PNDs consisting of SN-38 dimer and podophyllotoxin dimer with size in the range 30-50 nm was evaluated in human cancer HepG2, KPL-4, and MCF-7 cells. It was observed that the cytotoxicities of PNDs were changed depending on the type of cells. In addition, PNDs coated with polysorbate 80 showed higher activity than free PNDs, which suggests that the surface state of PNDs was the one of the important factors to affect cytotoxicity.
No preview · Article · Nov 2015 · Molecular Crystals and Liquid Crystals
[Show abstract][Hide abstract] ABSTRACT: In breast cancer, the prognosis of human epidermal growth factor receptor 2 (HER2)-positive patients (20-25%) has been dramatically improved by the clinical application of the anti-HER2 antibody drugs trastuzumab and pertuzumab. However, the clinical outcomes of HER2-negative cases with a poor prognosis have not improved, and novel therapeutic antibody drugs or diagnostic molecular markers of prognosis are urgently needed. Here, we targeted protease-activated receptor 1 (PAR1) as a new biomarker for HER2-negative patients. The developed anti-PAR1 antibody inhibited PAR1 activation by matrix metalloprotease 1 and thereby prevented cancer-cell migration and invasion. To estimate PAR1 expression levels in HER2-negative patient tissues using the antibody, user-friendly immunohistochemistry with fluorescence nanoparticles or quantum dots (QDs) was developed. Previously, immunohistochemistry with QDs was affected by tissue autofluorescence, making quantitative measurement extremely difficult. We significantly improved the quantitative sensitivity of immunohistochemistry with QDs by using an autofluorescence-subtracted image and single-QD imaging. The immunohistochemistry showed that PAR1 expression was strongly correlated with relapse-free survival time in HER2-negative breast cancer patients. Therefore, the developed anti-PAR1 antibody is a strong candidate for use as an anticancer drug and a prognostic biomarker for HER2-negative patients.
[Show abstract][Hide abstract] ABSTRACT: Mn-Zn ferrite, Mn1− x Zn x Fe2O4 nanoparticles encapsulated in amorphous SiO2 were prepared using our original wet chemical method. X-ray diffraction patterns confirmed that the diameters of these particles were within 7-30 nm. Magnetization measurements for various sample compositions revealed that the saturation magnetization (M s) of 7 nm particles was maximum for the x = 0.2 sample. AC magnetic susceptibility measurements were performed for Mn0.8 Zn 0.2Fe2O4 (x = 0.2) samples with 13-30 nm particles. The peak of the imaginary part of the magnetic susceptibility χ″ shifted to higher temperatures as the particle size increased. An AC field was found to cause the increase in temperature, with the 18 nm particles exhibiting the highest temperature increase, as expected. In addition, in vitro experiments were carried out to study the hyperthermia effects of Mn1− x Zn x Fe2O4 (x = 0.2, 18 nm) particles on human cancer cells.
Full-text · Article · May 2015 · Journal of Applied Physics
[Show abstract][Hide abstract] ABSTRACT: In this work, the authors performed X-ray imaging of mice using a colloid solution of Au nanoparticles that are coated with silica and subsequently surface-modified with poly(ethylene glycol) (PEG) (Au/SiO2/PEG). The silica-coating for Au nanoparticles and the amination for silica-coated particles were simultaneously performed in the presence of the Au nanoparticles, which were prepared by reducing Au ions (III) with sodium citrate in water at 80°C and by surface-modifying the Au nanoparticles with (3-aminopropyl)-trimethoxysilane (APMS), by a sol–gel process using tetraethylorthosilicate (TEOS), (3-aminopropyl)-triethoxysilane, water and sodium hydroxide (Au/SiO2-NH2). The surface modification of Au/SiO2-NH2 particles with PEG was performed by simply adding PEG with a functional group that reacts with an amino group to the Au/SiO2-NH2 particle colloid solution. A computed tomography value of the Au/SiO2/PEG colloid solution with an Au concentration of 0.129M was as high as 895 ± 8 HU. Mouse tissues were ...
[Show abstract][Hide abstract] ABSTRACT: The present work proposes preparation methods for quantum dot/silica (QD/SiO2) core-shell particles that immobilize Au nanoparticles (QD/SiO2/Au). A colloid solution of QD/SiO2 core-shell particles with an average size of 47.0 ± 6.1 nm was prepared by a sol-gel reaction of tetraethyl orthosilicate in the presence of the QDs with an average size of 10.3 ± 2.1 nm. A colloid solution of Au nanoparticles with an average size of 17.9 ± 1.3 nm was prepared by reducing Au3+ ions with sodium citrate in water at 80 °C. Introduction of amino groups to QD/SiO2 particle surfaces was performed using (3-aminopropyl)-triethoxysilane (QD/SiO2-NH2). The QD/SiO2/Au particles were fabricated by mixing the Au particle colloid solution and the QD/SiO2-NH2 particle colloid solution. Values of radiant efficiency and computed tomography for the QD/SiO2/Au particle colloid solution were 2.23 × 107 (p/s/cm2/sr)/(μW/cm2) at a QD concentration of 8 × 10−7 M and 1180 ± 314 Hounsfield units and an Au concentration of 5.4 × 10−2 M. The QD/SiO2/Au particle colloid solution was injected into a mouse chest wall. Fluorescence emitted from the colloid solution could be detected on the skin covering the chest wall. The colloid solution could also be X-ray-imaged in the chest wall. Consequently, the QD/SiO2/Au particle colloid solution was found to have dual functions, i.e., fluorescence emission and X-ray absorption in vivo, which makes the colloid solution suitable to function as a contrast agent for dual imaging processes.
[Show abstract][Hide abstract] ABSTRACT: This paper proposes a method for fabricating gadolinium diethylenetriamine pentaacetic acid-immobilized silica particles (SiO2/Gd-DTPA). Preparation of a colloid solution of spherical silica particles with an average size of 101.7±11.7 nm was performed by a sol-gel method at 35°C using 0.2 M tetraethylorthosilicate, 25 M H2O and 0.01 M NaOH in ethanol. Amino groups were introduced on the silica particles with 6 × 10−3 M (3- aminopropyl)triethoxysilane (APES) at 35°C (SiO2-NH2), which resulted in their average particle of 80.5±9.7 nm. Gd-DTPA was immobilized on the SiO2-NH2 particle surface with 5 × 10−4 M Gd-DTPA in 50/50 (v/v) water/dimethylformamide solution at 35°C , which provided their average particle of 101.6±12.3 nm. The APES-introduction and the Gd-DTPA-immobilization did not change the spherical structure, and shifted an iso-electric point of particles to higher pH for the APES-introduction and then to lower pH for the Gd-DTPA-immobilization, which indicated that APES and Gd-DTPA were successfully attached on the particle surface with no chemical damage. A relaxivity value for T1-weighted imaging of the SiO2/Gd-DTPA particle colloid solution was 2.7 mM−1 s−1, that was 64% of that for Magnevist. [DOI: 10.1380/ejssnt.2015.42]
Full-text · Article · Feb 2015 · e-Journal of Surface Science and Nanotechnology
[Show abstract][Hide abstract] ABSTRACT: This paper describes three findings. The first is a method for producing colloidal solutions of quantum dot (QD) nanoparticles with silica shells (QD/SiO2). QD nanoparticles averaging 10.3±2.1 nm in size were coated with silica via a sol–gel reaction with tetraethyl orthosilicate using NaOH as a catalyst. The QD/SiO2 particle size could be varied by varying the QD concentration. The average particle sizes were 19.1±3.0 (S-QD/SiO2) and 47.0±6.1 nm (L-QD/SiO2) for QD concentrations of 6.4×10−9 M (4.6×1011 particles/L) and 6.4×10−10 M (4.6×1010 particles/L), respectively. The second finding is a method to modify the particle surface with poly(ethylene glycol), which is called PEGylation (QD/SiO2/PEG). S-QD/SiO2 and L-QD/SiO2 were PEGylated using methoxy polyethylene glycol silane (S-QD/SiO2/PEG and L-QD/SiO2/PEG, respectively). The third finding is an in-vivo fluorescence imaging technique using the QD/SiO2/PEG particle colloid solutions. Both QD/SiO2/PEG particle colloid solutions fluoresced with intensities comparable with that of the QD colloid solution. Mouse tissues could be imaged by injecting the QD/SiO2/PEG colloid solution into them and measuring the emitted fluorescence intensity. The L-QD/SiO2/PEG particles did not form aggregates in blood, which allowed the particles to reach the tissues more efficiently than the S-QD/SiO2/PEG particles.
No preview · Article · Feb 2015 · Journal of chemical engineering of Japan
[Show abstract][Hide abstract] ABSTRACT: Neoadjuvant chemotherapy has been increasingly utilized in the treatment of breast cancer patients. However, there are no established surrogate markers predicting the response to subsequent adjuvant therapy and clinical outcome of patients. In particular, whether primary or lymph nodes metastasis should be evaluated for these analyses has remained unknown. Therefore, in this study, we first evaluated the differences in biomarkers between primary and metastatic cancer tissues in the patients undergoing neoadjuvant chemotherapy. We then correlated the findings with the clinical outcomes of these patients.
We examined 49 patients receiving neoadjuvant chemotherapy and subsequent surgery with lymph node metastasis. Estrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2) and Ki-67 were all immunohistochemically evaluated in core needle biopsy samples from primary and metastatic tumors following chemotherapy.
No statistically significant differences in these markers were detected between the primary tumor and metastatic lymph nodes following therapy, but the Ki-67 labeling index was significantly higher in metastatic lymph nodes than in primary tumor (p = 0.017). The patients associated with luminal A type carcinoma in their lymph nodes following chemotherapy demonstrated significantly better clinical outcomes (disease-free survival: p = 0.0045, overall survival: p = 0.0006) than those who were not.
These data indicate that subtype classification following chemotherapy, in the metastatic lymph nodes rather than primary tumor could predict long-term outcomes of patients undergoing neoadjuvant chemotherapy.
No preview · Article · Dec 2014 · The International journal of biological markers
[Show abstract][Hide abstract] ABSTRACT: This work proposes a method for fabricating silica-coated gold (Au) nanoparticles, surface modified with poly(ethylene glycol) (PEG) (Au/SiO2/PEG), with a particle size of 54.8 nm. X-ray imaging of a mouse is performed with the colloid solution. A colloid solution of 17.9 nm Au nanoparticles was prepared by reducing Au ions (III) with sodium citrate in water at 80 °C. The method used for silica-coating the Au nanoparticles was composed of surface-modification of the Au nanoparticles with (3-aminopropyl)-trimethoxysilane (APMS) and a sol–gel process. The sol–gel process was performed in the presence of the surface-modified Au nanoparticles using tetraethylorthosilicate, APMS, water, and sodium hydroxide, in which the formation of silica shells and the introduction of amino groups to the silica-coated particles took place simultaneously (Au/SiO2–NH2). Surface modification of the Au/SiO2–NH2 particles with PEG, or PEGylation of the particle surface, was performed by adding PEG with a functional group that reacted with an amino group in the Au/SiO2–NH2 particle colloid solution. A computed tomography (CT) value of the aqueous colloid solution of Au/SiO2/PEG particles with an actual Au concentration of 0.112 M was as high as 922 ± 12 Hounsfield units, which was higher than that of a commercial X-ray contrast agent with the same iodine concentration. Injecting the aqueous colloid solution of Au/SiO2/PEG particles into a mouse increased the light contrast of tissues. A CT value of the heart rose immediately after the injection, and this rise was confirmed for up to 6 h.
No preview · Article · Aug 2014 · Journal of Nanoparticle Research
[Show abstract][Hide abstract] ABSTRACT: This work describes X-ray imaging of mouse using colloid solution of silica coated Au (Au/SiO2) nanoparticles surface modified with poly(ethylene glycol) (PEG) (Au/SiO2/PEG). A colloid solution of Au nanoparticles was prepared by reducing Au ions (III) with sodium citrate. Au/SiO2 nanoparticles were fabricated by a sol–gel method using tetraethylorthosilicate, water and sodium hydroxide in ethanol in the presence of Au nanoparticles surface modified with (3-aminopropyl)trimethoxysilane. A computed tomography value of the Au/SiO2 colloid solution with an Au concentration of 0·083M was as high as 1421·2 Hounsfield units, which was higher than that of a commercial X-ray contrast agent with the same iodine concentration. Surface modification of the Au/SiO2 particles with PEG, or PEGylation of the particle surface, was performed using (3-aminopropyl)trimethoxysilane and PEG for the Au/SiO2 particles. Tissues of mouse could be imaged by injecting the colloid solutions of Au/SiO2 particles or Au/SiO2/PEG particles into it. The PEGylation provided an increase in residence time of particles in the mouse.
No preview · Article · Nov 2013 · Material Research Innovations
[Show abstract][Hide abstract] ABSTRACT: The present work proposes a preparation method for multilayered Au nanoparticle/silica/gadolinium compound/silica (Au/SiO2/GdC/SiO2) core–shell particles. Silica-coated Au (Au/SiO2) core–shell particles with a size of 47.3 nm were prepared by a sol–gel reaction in the presence of the Au nanoparticles with a size of 16.9 nm prepared through a citrate-reduction method. Multilayered Au/silica/gadolinium compound (Au/SiO2/GdC) core–shell particles with a size of 55.0 nm were prepared by a homogeneous precipitation reaction in the presence of the Au/SiO2 particles. The Au/SiO2/GdC/SiO2 particles with a size of submicron meter were fabricated by the sol–gel reaction in the presence of the Au/SiO2/GdC particles.
[Show abstract][Hide abstract] ABSTRACT: A preparation method for gadolinium compound (GdC) nanoparticles coated with silica () is proposed. GdC nanoparticles were prepared with a homogeneous precipitation method at using M , 0.5 M urea and M ethylenediarinnetetraacetic acid disodium salt dihydrate (ETDA) in water. As a result of preparation at various EDTA concentrations, GdC nanoparticles with a size as small as nm, which were colloidally stable, were prepared at an EDTA concentration of M. Silica-coating of the GdC nanoparticles was performed by a Stber method at using M tetraethylorthosilicate (TEOS), 11 M and M NaOH in ethanol in the presence of M GdC nanoparticles. Performance of preparation at various TEOS concentrations resulted in production of particles with an average size of nm at a TEOS concentration of M. The gadolinium (Gd) concentration of M in the as-prepared particle colloid solution was increased up to a Gd concentration of 0.2 M by concentrating with centrifugation. The core-shell structure of particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated colloid solution showed images of X-ray and magnetic resonance with contrast as high as commercial Gd complex contrast agents.
[Show abstract][Hide abstract] ABSTRACT: This work performed X-ray imaging of mouse by using aqueous colloid solution of AgI nanoparticles coated with silica (AgI/SiO2) and then surface-modified with poly(ethylene glycol) (PEG) (AgI/SiO2/PEG). A colloid solution of AgI nanoparticles was prepared by mixing silver perchlorate and potassium iodide in water. The AgI nanoparticles were surface-modified with 3-mercaptopropyltrimethoxysilane and then were silica-coated by a sol-gel reaction between tetraethylorthosilicate and H2O catalyzed with NaOH in ethanol. The AgI/SiO2 particle surface was modified with PEG by using methoxy PEG silane . The AgI/SiO2/PEG colloid solution revealed a computed tomography value as high as 1343.6 HU at an iodine concentration of 0.1 M, which was higher than a commercial X-ray contrast agent with the same iodine concentration. Tissues of mouse could be imaged by injecting the concentrated colloid solution into them.
[Show abstract][Hide abstract] ABSTRACT: The mechanisms underlying the cellular entry of the HIV-1-Tat protein transduction domain (TatP) and the molecular information necessary to improve the transduction efficiency of TatP remain unclear due to the technical limitations for direct visualization of TatP's behavior in cells. Using confocal microscopy, total internal reflection fluorescence microscopy, and four-dimensional microscopy, we developed a single-molecule tracking assay for TatP labeled with quantum dots (QDs) to examine the kinetics of TatP initially and immediately before, at the beginning of, and immediately after entry into living cells. We report that even when the number of multivalent-TatP (mTatP)-QDs bound to a cell was low, each single mTatP-QD first locally induced the cell's lateral transport machinery to move the mTatP-QD toward the center of the cell body upon crosslinking of heparan-sulfate proteoglycans (HSPGs). The centripetal and lateral movements were linked to the integrity and flow of actomyosin and microtubules. Individual mTatP underwent lipid raft-mediated temporal confinement, followed by complete immobilization, which ultimately led to endocytotic-internalization. However, bivalent-TatP did not sufficiently promote either cell-surface movement or internalization. Together, these findings provide clues regarding the mechanisms of TatP cell-entry and indicate that increasing the valence of TatP on nanoparticles allows them to behave as cargo-delivery nanomachines.
Full-text · Article · Jun 2013 · Molecular and Cellular Biology
[Show abstract][Hide abstract] ABSTRACT: A preparation method for Gd-ethylenediaminetetraacetic acid disodium salt dihydrate (ETDA) complex-immobilized silica particles
(Gd-EDTA/SiO2) is proposed. Preparation of spherical silica particles was performed by a sol-gel method at 35°C
using 0.2 M tetraethylorthosilicate, 25 M H2O, and 0.01 M NaOH in ethanol, which produced silica particles with an
average size of nm. Immobilization of Gd-EDTA on the silica particles was conducted at 35°C by introducing amino groups on the silica particles with (3-aminopropyl)trimethoxysilane at pH 3 (NH2/SiO2) and then making Gd-EDTA act on the NH2/SiO2 particles at pH 5. The as-prepared Gd-EDTA/SiO2 particle colloid solution was concentrated up to a Gd concentration of 0.347 mM by centrifugation. The sphere structure of Gd-EDTA/SiO2 particles was undamaged, and the colloid solution was still colloidally stable, even after the concentrating process. The concentrated Gd-EDTA/SiO2 colloid solution revealed good MRI properties. A relaxivity value for T1-weighted imaging was as high as 5.15 mM−1 s−1, that was comparable to that for a commercial Gd complex contrast agent.
[Show abstract][Hide abstract] ABSTRACT: This paper describes a method for producing silica particles containing multiple quantum dots (QD/SiO2), a method for surface-modifying the particles with poly(ethylene glycol) (QD/SiO2/PEG), and an in vivo fluorescence imaging technique using colloid solution of the QD/SiO2/PEG particles. The QDs used were ZnS-coated CdSexTe1−x
nanoparticles surface-modified with carboxyl groups, and had an average size of 10.3 ± 2.1 nm. The QD/SiO2 particles were fabricated by performing sol–gel reaction of tetraethyl orthosilicate using NaOH as a catalyst in the presence of the QDs. The produced particles formed core–shell structure composed of multiple QDs and silica shell, and had an average size of 50.2 ± 17.9 nm. Surface-modification of the QD/SiO2 particles with PEG, or PEGylation of the particle surface, was performed by using methoxy polyethylene glycol silane. Fluorescence of QD colloid solution was not quenched even through the silica-coating and the PEGylation. Tissues of a mouse could be imaged by injecting the concentrated colloid solution into it and measuring fluorescence intensity emitted from the tissues.
No preview · Article · Apr 2013 · Journal of Sol-Gel Science and Technology
[Show abstract][Hide abstract] ABSTRACT: A preparation method for hollow particles composed of silica shell containing gadolinium compound (GdC) is proposed. GdC nanoparticles with an average size of 40.5 ± 6.2 nm were prepared with a homogeneous precipitation method at 80°C using 1.0 × 10−3 M Gd(NO3)3 and 0.5 M urea in the presence of 2.0 × 10−4 M ethylenediaminetetraacetic acid disodium salt dihydrate. Silica-coated GdC (GdC/SiO2) nanoparticles with an average size of 100.9 ± 9.9 nm were fabricated with a sol-gel method at 35°C using 5.0 × 10−3 M tetraethylorthosilicate, 11 M H2O, and 1.5 × 10−3 M NaOH in ethanol in the presence of 1.0 × 10−3 M GdC nanoparticles. The GdC/SiO2 particles were aged at 80°C in water after replacement of solvent of the as-prepared GdC/SiO2 particle colloid solution with water, which provided diffusion of GdC into the silica shell and then formation of a hollow structure. The hollow particle colloid solution revealed good MRI properties. A relaxivity value for longitudinal relaxation time-weighted imaging was as high as 3.38 mM−1 · s−1 that attained 80% of that for a commercial Gd complex contrast agent.